Young children spend a lot of time at home, yet there is little empirical research on how they spend that time and how it relates to developmental outcomes. Prior research suggests less-structured time--where children practice making choices and setting goals--may develop "self-directed" executive function in 6-year-olds. But less-structured time may be related to executive function for other reasons--for example, because it provides opportunities to acquire conceptual knowledge relevant to using executive function on tasks. We thus tested the possibility that less-structured time is also related to younger children's "externally cued" executive function. In this remote online study, caregivers of 93 3- to 5-year-olds indicated the amount of time their child was typically spending in various activities while at home during the early phase of the COVID-19 pandemic. Activities were categorized as "structured" (primarily lessons with specific goals defined by adults or an app), "less-structured" (wide range of activities permitting choice and interaction with caregiver), "passive" (e.g., watching TV or videos), and "primarily physical" (e.g., bike riding). Children's externally cued executive function was assessed via the Dimensional Change Card Sort (DCCS). Time and variety in less-structured activities were related to successful switching on the DCCS, controlling for age, family income, caregiver education, and verbal knowledge. Caregivers were more involved in less-structured versus structured activities. Caregiver ratings of children's temperament were related to how children's time was spent. These findings suggest several new avenues for studying young children's activities at home and their relations with developmental outcomes. A video abstract of this article can be viewed at https://youtu.be/3aGmpSnjuCs